1. Field of the Invention
This invention relates generally to a design of devices and systems for safely and effectively accessing tissue. The invention provides a device and system that can be easily steered through tissue within a patient from a location outside the patient's body. The system also provides a platform for delivery of materials and devices to a target site or anatomic location within a body.
2. Description of Related Art
A variety of needles, lancets, trocars, stylets, cannulas, devices and systems for examining, diagnosing, treating, or removing tissue from a patient are known in the art. See, U.S. Pat. No. 4,013,080 entitled Cannula Connector and Director Indicator Means for Injection System (Froning); U.S. Pat. No. 4,769,017 entitled Self-Sealing Infusion Manifold and Catheter Connector (Fath et al); U.S. Pat. No. 5,240,011 entitled Motorized Biopsy Needle Positioner (Assa); U.S. Pat. No. 5,526,821 entitled Biopsy Needle with Sample Retaining Means (Janshidi); U.S. Pat. No. 5,660,185 entitled Image-Guided Biopsy Apparatus with Enhanced Imaging and Methods (Shmulewitz); U.S. Pat. No. 5,735,264 entitled Motorized Mammographic Biopsy Apparatus (Siczek et al); U.S. Pat. No. 6,315,737 B1 entitled Biopsy Needle for a Biopsy Instrument (Skinner); U.S. Pat. No. 6,328,701 B1 entitled Biopsy Needle and Surgical Instrument (Terwilliger); U.S. Pat. No. 6,402,701 B1 entitled Biopsy Needle Instrument (Kaplan); U.S. Pat. No. 6,464,648 B1 entitled Biopsy Device and Remote Control Device Therefor (Nakamura); U.S. Pat. No. 6,485,436 B1 entitled Pressure-Assisted Biopsy Needle Apparatus and Technique (Truckai et al); U.S. Pat. No. 6,558,337 B2 entitled Positioner for Medical Devices such as Biopsy Needles (Dvorak et al); U.S. Pat. No. 6,709,408 B2 entitled Dual Action Aspiration Biopsy Needle (Fisher); U.S. Pat. No. 6,908,440 B2 entitled Dual Action Aspiration Biopsy Needle (Fisher); and U.S. Pat. No. 6,918,881 B2 entitled Biopsy Needle with Integrated Guide Pin (Miller et al). U.S. Patent Publications US 2004/0133168 A1 entitled Steerable Needle (Salcudean et al.); as well as PCT Publications WO 00/13592 A1 entitled Device for Receiving and Actuating a Biopsy Needle (Heinrich); WO 03/077768 A1 entitled Biopsy Needle and Biopsy Needle Module that Can be Inserted into the Biopsy Device (Heske et al); WO 2004/062505 A1 entitled Flexible Biopsy Needle (Bates et al.); and WO 2004/086977 A1 entitled Coaxial Cannula Provided with a Sealing Element (Heske et al.).
For example, biopsy needles are used in the medical field to remove tissue, cells or fluids from a body for examination and diagnostic testing. Biopsy needles can form part of a biopsy system. Currently, there are three main types of procedures that are used to obtain a biopsy, or tissue sample. First, a surgeon can use a scalpel, or other suitable cutting instrument, to make an incision in a patient that is large enough for the surgeon to access the tissue to be tested. One or more large pieces of a target site, such as a tumor, lesion, cells or fluid, are then removed and tested for malignancy. This procedure is typically performed under general anesthesia.
Another technique, the core tissue biopsy procedure, uses a large bore needle to cut or shear away one or more visible pieces of a tumor or lesion. The pieces of tissue obtained using a large bore needle are visible to the unaided eye and may require further processing to view through a microscope (i.e., due to the size and thickness of the tissue pieces obtained).
Yet another technique is the use of fine needle aspiration (FNA) needles with small bores to obtain tissue samples. A needle is used with a syringe to access the target site. Negative pressure is created in the syringe, and as a result of the pressure difference between the syringe and the mass, cellular material can be drawn into the syringe and removed. Typically, the needle is moved in and out in order to facilitate obtaining enough tissue or material to examine and make a diagnosis.
There are many medical conditions for which a physician might wish to obtain access to a target site or obtain a sample of tissue or material from a patient. For example, pulmonary disorders affect millions of Americans, and many more individuals worldwide, each year. While some pulmonary disorders are chronic (e.g., chronic obstructive pulmonary disease (COPD)), many are acute and deadly. For example, lung cancer is the leading cause of death attributable to cancer for both men and women. More people die of lung cancer, than die of breast, prostate and colon cancer combined. It is estimated that in the United States alone, over 170,000 new cases of lung cancer are diagnosed each year. Of those people diagnosed with lung cancer, the prognosis is grim: 6 of 10 will die within one year of being diagnosed and between 7 and 8 will die within two years of diagnosis.
Most lung cancers start in the lining of the bronchi (plural for bronchus), although lung cancer can start in other parts of the lung as well. Since it generally takes many years for lung cancer to develop, there can be areas of pre-cancerous changes in the lung long before the formation of lung cancer. With currently available technology, the pre-cancerous changes are often not detected because the changes cannot be seen on an x-ray and do not cause symptoms early on that would cause a patient to seek medical attention. It is for this reason that most people with lung cancer are not diagnosed during the critical early stages of the disease.
Taking chest x-rays and checking sputum under a microscope for the appearance of cancer cells had been performed for screening but was found to be unreliable, and thus is not even recommended screening for persons of high risk (e.g., those people who smoke). Recently, spiral CT scanning has shown promise as a potential screening tool for finding lung cancer at an early stage. However, at this juncture it is not known whether the use of spiral CT scans improves the prognosis for long-term survival by increasing the early detection of the disease. Even with a scan indicating the possible presence of pre-cancerous tissue, the ability to take a biopsy for testing is difficult without causing the lungs to collapse, which can result in a required hospital stay.
Each condition where access to tissue for examining or diagnosing a condition, or where obtaining a biopsy would be desirable, presents its own challenges. The, lung, however, presents a useful platform for understanding issues relating to accessing and treating target sites as well as obtaining biopsies.
In the lung, any time a procedure requires an instrument to be inserted through an incision in the chest wall, the pleural layers surrounding the lung are pierced or compromised. As a result of the propensity for transthoracic procedures to cause, for example, pneumothorax, there is a limitation on the outer diameter of the instruments that are used for these procedures. This is a significant drawback for procedures such as percutnaeous transthoracic lung tissue biopsy, where the interventionalist introduces a biopsy needle through the chest wall. Other procedures which are limited when applied to transthoracic procedures include percutaneous transthoracic needle aspiration (PTNA), mediastinoscopy, thorascopy and drainage of pleural effusions. Air leaks and bleeding frequently occur either during insertion or removal of the device through the opening in the pleural lining of the chest cavity. Even when using small needles of 19-23 gauge, the incidence of pneumothorax is relatively high, being in the range of 30-40% and the incidence of hemothorax is 25%. Because of the anatomical challenges and physiological mechanics of the lung, accessing the target site or anatomic location on a first attempt is very important.
Even during the biopsy process currently practiced, multiple tissue samples or cores may be taken through the smallest gauge needle possible in an effort to increase biopsy efficacy while decreasing the likelihood of, for example, pneumothorax. However, each time the needle is reinserted, the chances for pneumothorax or bleeding increase. Additionally, due to the small size of the multiple samples, the pathologist may not have the benefit of a sample size large enough to improve the accuracy of diagnosis.
Thus, there exists a need for devices and methods that provide minimally invasive access to a target site or anatomic location, such as lung tissue, for diagnostics and treatment which are able to access the target site more accurately. In the context of the lung, there is a need for such a device that does not increase the risk of causing the lung to collapse, or air or blood entering the pleural space. The present invention satisfies these needs and provides related advantages as well.